From mboxrd@z Thu Jan  1 00:00:00 1970
From: will.deacon@arm.com (Will Deacon)
Date: Mon, 7 Oct 2013 11:49:36 +0100
Subject: [PATCH] ARM: tlb: __flush_tlb_mm need to use int asid var for BE
 correct operation
In-Reply-To: <20131007104524.GK12758@n2100.arm.linux.org.uk>
References: <1381128458-32140-1-git-send-email-victor.kamensky@linaro.org>
 <1381128458-32140-2-git-send-email-victor.kamensky@linaro.org>
 <20131007104524.GK12758@n2100.arm.linux.org.uk>
Message-ID: <20131007104936.GG465@mudshark.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Oct 07, 2013 at 11:45:24AM +0100, Russell King - ARM Linux wrote:
> On Sun, Oct 06, 2013 at 11:47:38PM -0700, Victor Kamensky wrote:
> > __flush_tlb_mm function need to use intermediate 'int' type 'asid'
> > variable int tlb_op macro call. Direct use of ASID macro produces
> > 64 bit unsigned long long type passed to inline assembler statement
> > as 'r' operand (32bit), and resulting behavior is not well specified.
> > It works in little endian case, but is broken in big endian case. In
> > big endian case gcc generate such code that 0 is passed to
> > 'mcr	15, 0, r4, cr8, cr3, {2}' operation.
> > 
> > Note other functions like __local_flush_tlb_mm, and local_flush_tlb_mm
> > already use intermediate 'asid' variable in similar code.
> 
> A much better solution would be to ensure that ASID() only returns
> the 'unsigned' type, not a long long type.
> 
> #define ASID(mm)        ((unsigned)(mm)->context.id.counter & ~ASID_MASK)

Yup, that looks good to me. This is similar to the problem Ben already fixed
in the mmid macro, so I think this should be included as part of his BE
series.

Speaking of which -- it's probably a good time to refresh and repost that if
we're aiming for 3.13...

Will